Metarhizium acridum | |
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Red locust with sporulating standard isolate of M. acridum | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Sordariomycetes |
Order: | Hypocreales |
Family: | Clavicipitaceae |
Genus: | Metarhizium |
Species: | M. acridum |
Binomial name | |
Metarhizium acridum (Driver & Milner) J.F. Bisch., Rehner & Humber (2009) | |
Synonyms | |
Metarhizium anisopliae var. acridumDriver & Milner Contents |
Metarhizium acridum [1] is the new name given to a group of fungal isolates that are known to be virulent and specific to the Acrididea (grasshoppers). Previously, this species has had variety status in Metarhizium anisopliae (var. acridum [2] ); before that, reference had been made to M. flavoviride or Metarhizium sp. [3] describing an "apparently homologous and distinctive group" of isolates that were most virulent against Schistocerca gregaria (desert locust) in early screening bioassays.
M. acridum almost exclusively infects grasshoppers (order Orthoptera): researchers believe that this has to do with the Mest1 gene which is not present in M. acridum. By taking a strain of M. robertsii that has a nonfunctioning Mest1 gene, researchers found that the mutant was only able to infect Melanoplus femurrubrum , which is consistent with M. acridum activity. This allows the initiation of the infection process on the specific targets. The expression of Mest1 in the entomopathogen M. acridum is triggered by substances that are only found on the waxy coat of the grasshoppers, which explains why this pathogen specifically only targets grasshoppers and locusts. [4]
M. acridum has been used to control locusts and other grasshopper pest species: originally by the international LUBILOSA programme (which developed the product Green Muscle). This team identified and addressed key technical challenges for exploitation of microbial control agents, including isolate selection, mass production, and delivery systems (formulation and application). [5] [6] Insect control (mortality) depends on factors such as the number of spores applied against the insect host, the formulation [7] and weather conditions. [8] Oil-based formulations allow the application of fungal spores under dry conditions, and are compatible with existing ultra-low volume (ULV) application techniques for locust control.
As of 2012, M. acridum was under consideration by the USDA for release in the Western U.S. for control of native grasshoppers and crickets. [9]
Locusts are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstances they become more abundant and change their behaviour and habits, becoming gregarious. No taxonomic distinction is made between locust and grasshopper species; the basis for the definition is whether a species forms swarms under intermittently suitable conditions; this has evolved independently in multiple lineages, comprising at least 18 genera in 5 different subfamilies.
Grasshoppers are a group of insects belonging to the suborder Caelifera. They are amongst what are possibly the most ancient living groups of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago.
The desert locust is a species of locust, a periodically swarming, short-horned grasshopper in the family Acrididae. They are found primarily in the deserts and dry areas of northern and eastern Africa, Arabia, and southwest Asia. During population surge years, they may extend north into parts of Southern Europe, south into Eastern Africa, and east in northern India. The desert locust shows periodic changes in its body form and can change in response to environmental conditions, over several generations, from a solitary, shorter-winged, highly fecund, non-migratory form to a gregarious, long-winged, and migratory phase in which they may travel long distances into new areas. In some years, they may thus form locust plagues, invading new areas, where they may consume all vegetation including crops, and at other times, they may live unnoticed in small numbers.
A Biopesticide is a biological substance or organism that damages, kills, or repels organisms seens as pests. Biological pest management intervention involves predatory, parasitic, or chemical relationships.
An entomopathogenic fungus is a fungus that can kill or seriously disable insects. They do not need to enter an insect's body through oral ingestion or intake; rather, they directly penetrate though the exoskeleton.
Metarhizium robertsii is a fungus that grows naturally in soils throughout the world and causes disease in various insects by acting as a parasitoid. It is a mitosporic fungus with asexual reproduction, which was formerly classified in the form class Hyphomycetes of the phylum Deuteromycota.
Raymond J. St. Leger is an American mycologist, entomologist, molecular biologist and biotechnologist who currently holds the rank of Distinguished University Professor in the Department of Entomology at the University of Maryland, College Park.
Metarhizium is a genus of entomopathogenic fungi in the Clavicipitaceae family. With the advent of genetic profiling, placing these fungi in proper taxa has now become possible. Most turn out to be the asexual forms (anamorphs) of fungi in the phylum Ascomycota, including Metacordyceps spp.
The Senegalese grasshopper is a medium-sized grasshopper species found in the Sahel region of Africa, the Canary Islands, Cape Verde Islands, and West Asia. Although not called a locust in English, this species shows gregarious behaviour and some morphological change on crowding. In many parts of the Sahel, this species may cause greater year-on-year crop damage than better-known locusts, attacking crops such as the pearl millet.
LUBILOSA was the name of a research programme that aimed at developing a biological alternative to the chemical control of locusts. This name is an acronym of the French title of the programme: Lutte Biologique contre les Locustes et les Sauteriaux. During its 13-year life, the programme identified an isolate of an entomopathogenic fungus belonging to the genus Metarhizium and virulent to locusts, and went through all the necessary steps to develop the commercial biopesticide product Green Muscle based on its spores.
The brown locust is a medium-sized small locust species in the monotypic genus Locustana. It is found in Southern Africa and shows classic gregarious behaviour with phase polymorphism on crowding.
Metarhizium majus is the name given to a group of fungal isolates that are known to be virulent against Scarabaeidae, a family of beetles. Previously, this species has had variety status in Metarhizium anisopliae and its name is derived from characteristically very large spores for the genus Metarhizium. There has been considerable interest in developing isolates of this species into mycoinsecticides: especially against the coconut and oil palm beetle pest Oryctes in SE Asia, the Pacific region and Africa.
Metarhizium flavoviride is a Sordariomycete in the order Hypocreales and family Clavicipitaceae. The genus Metarhizium currently consists of over 70 described species and are a group of fungal isolates that are known to be virulent against Hemiptera and some Coleoptera. M. flavoviride is described as its own species, but there also exists a variety of M. flavoviride, which is M. flavoviride var. flavoviride. Previously described varieties of M. flavoviride have been documented, however recent random amplified polymorphic DNA (RAPD) markers have assigned these varieties as new species. The reassigned species are as follows: M. flavoviride Type E is now M. brasiliense; M. flavoviride var. minus is now M. minus; M. flavoviride var. novozealandicum is now M. novozealandicum; and M. flavoviride var. pemphigi is now M. pemphigi.
Lecanicillium muscarium is the approved name of an entomopathogenic fungus species, that was previously widely known as Verticillium lecanii (Zimmerman) Viegas), but is now understood to be an anamorphic form in the Cordyceps group of genera in the Cordycipitaceae. It now appears that isolates formerly classified as V. lecanii could be L. attenuatum, L. lecanii, L. longisporum, L. muscarium or L. nodulosum. For example, several recent papers, such as Kouvelis et al. carried out mitochondrial DNA studies, refer to this name.
Muscardine is a disease of insects. It is caused by many species of entomopathogenic fungus. Many muscardines are known for affecting silkworms. Muscardine may also be called calcino.
Metarhizium brunneum is the re-instated name of a group of reassigned Metarhizium isolates, previously grouped in the species "Metarhizium anisopliae var. anisopliae": based on a multigene phylogenetic approach using near-complete sequences from nuclear DNA. It is a mitosporic fungus with asexual reproduction, which was formerly classified in the form class Hyphomycetes of the form phylum Deuteromycota. M. brunneum has been isolated from Coleoptera, Lepidoptera, Diptera and soil samples, but a commercially developed isolate (below) has proved virulent against Hemiptera and Thysanoptera.
Entomophaga grylli is a fungal pathogen which infects and kills grasshoppers. It is the causal agent of one of the most widespread diseases affecting grasshoppers. This is sometimes known as summit disease because infected insects climb to the upper part of a plant and grip the tip of the stem as they die; this ensures widespread dispersal of the fungal spores. The fungus is a species complex with several different pathotypes, each one of which seems to be host-specific to different subfamilies of grasshoppers. The pathogen is being investigated for its possible use in biological pest control of grasshoppers.
Social immunity is any antiparasite defence mounted for the benefit of individuals other than the actor. For parasites, the frequent contact, high population density and low genetic variability makes social groups of organisms a promising target for infection: this has driven the evolution of collective and cooperative anti-parasite mechanisms that both prevent the establishment of and reduce the damage of diseases among group members. Social immune mechanisms range from the prophylactic, such as burying beetles smearing their carcasses with antimicrobials or termites fumigating their nests with naphthalene, to the active defenses seen in the imprisoning of parasitic beetles by honeybees or by the miniature 'hitchhiking' leafcutter ants which travel on larger worker's leaves to fight off parasitoid flies. Whilst many specific social immune mechanisms had been studied in relative isolation, it was not until Sylvia Cremer et al.'s 2007 paper "Social Immunity" that the topic was seriously considered. Empirical and theoretical work in social immunity continues to reveal not only new mechanisms of protection but also implications for understanding of the evolution of group living and polyandry.
Donald W. Roberts was an American insect pathologist and one of the originators of that field. He was especially known for research into biological pest control of Lepidoptera by Metarhizium but also Beauveria bassiana. He was a Research Professor Emeritus in the Biology Department of Utah State University.
Metarhizium anisopliae is the type species in its genus of fungi, that grows naturally in soils throughout the world and causes disease in various insects by acting as a parasitoid. Ilya I. Mechnikov named it Entomophthora anisopliae (basionym) after the insect species from which it was originally isolated – the beetle Anisoplia austriaca and from these early days, fungi such as this have been seen as potentially important tools for pest management. It is a mitosporic fungus with asexual reproduction, which was formerly classified in the form class Hyphomycetes of the phylum Deuteromycota.
Zhang, L; Lecoq, M. (2021). Nosema locustae (Protozoa, Microsporidia), a biological agent for locust and grasshopper control. Agronomy 11, 711. DOI:10.3390/agronomy11040711